Oxidative stress and potential applications of free radical scavengers in glaucoma

Abstract

Glaucoma is the leading cause of irreversible blindness in industrialized countries and comprises a group of diseases characterized by progressive optic nerve degeneration. Glaucoma is commonly associated with elevated intraocular pressure due to impaired outflow of aqueous humor resulting from abnormalities within the drainage system of the anterior chamber angle (open-angle glaucoma) or impaired access of aqueous humor to the drainage system (angle-closure glaucoma). Oxidative injury and altered antioxidant defense mechanisms in glaucoma appear to play a role in the pathophysiology of glaucomatous neurodegeneration that is characterized by death of retinal ganglion cells. Oxidative protein modifications occurring in glaucoma serve as immunostimulatory signals and alter neurosupportive and immunoregulatory functions of glial cells. Initiation of the apoptotic cascade observed in glaucomatous retinopathy can involve oxidant mechanisms and different agents have been shown to be neuroprotective. This review focuses on the molecular mechanisms of oxidant injury and summarizes studies that have investigated novel free radical scavengers in the treatment of glaucomatous neurodegeneration.

Oxidative stress in dry age-related macular degeneration and exfoliation syndrome

“…Three important ROS in organisms are hydrogen peroxide (H 2 O 2 ), the hydroxyl radical (OHÁ) and the superoxide radical (O À 2 ). In order to minimize oxidative stress, cells possess their own antioxidant system that includes three major antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT), and a number of other non-enzyme molecules, such as glutathione (GSH) and its oxidized form, glutathione disulfide (GSSG) 3 Figure 1). Moreover, glutathione S-transferase and glutathione reductase, as well as glutathione itself, in combination, play an important role in the antioxidant defense system.…”

“…Crit Rev Clin Lab Sci, Early Online:[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Critical Reviews in Clinical Laboratory Sciences Downloaded from informahealthcare.com by University of Glasgow on 01/04/15For personal use only.…”

A two‐year follow‐up of oral antioxidant supplementation in primary open‐angle glaucoma: an open‐label, randomized, controlled trial

“…Oxidative stress, a cytopathic consequence of the disbalance between excessive reactive oxygen species (ROS) production and/or the insufficient suppression of ROS removal by the antioxidant defence system, has been implicated in glaucoma according to studies carried out in animals and humans (Kumar & Agarwal 2007;Zanon-Moreno et al 2008;Chrysostomou et al 2013;Pinazo-Duran et al 2013;Aslan et al 2013;Pinazo-Duran et al 2014). Thus theoretically, the intake of nutritional antioxidants may have a beneficial impact on patients with glaucoma, as suggested in other ocular disorders such as age-related macular degeneration (ARMD), diabetic retinopathy or uveitis (The AREDS Research Group 2001;Richer et al 2004;Garcia-Medina et al 2011;Yadav et al 2011; Age-Related Eye Disease Study 2 Research Group 2013).…”

Oxidative Stress in the Pathogenesis of Corneal Endothelial Dystrophies and Other Corneal Diseases

“…Oxidative stress has also played a pivotal role in numerous ocular diseases. Some of these diseases include cataract [1], openangle glaucoma [2], age-related macular degeneration [3], uveitis [4,5], and retinopathy of prematurity [6]. The cornea, iris, and lens constitute the anterior part of the eye and are constantly exposed to the outside environment comprising of radiation, industrial smoke, vapors, and chemical gases.…”